animated and paint with project Dogwaffle


Modeling of a Holder for Coasters

with Amapi 4.15
by Don Felipe

Here's an easy exercise: how to model a holder for coasters, you know, the kind you have sitting on your coffee table.

These are the various things and tools done herein:

 
1. Start
2. Top View
3. Draw a Box
4. Extrude the box and close (cap) it
5. Round the corners
6. Bevel the top edges
7. Extract a Curve for the Pilars
8. Offset the curve
9. Duplicate by Rotation
10. Finish
11. Movies

Here's the finished image:

and another one:

You'll notice this was rendered  and modeled in Amapi 3D v4.1 under Windows 95, I used a coffee table model that's included in the pack to put my final design on it. I applied various wooden textures and gave the table a little gloss to reflect the environment. Notice also the soft shadows, there are 3 light sources in this example.

Here's how I did this:

1. Start

Start Amapi 3D and select the NDI (Natural Design Interface), you know, the one some people call 'weird' or 'corky', well you'll soon find out it's the right one for you.
Hit the ('/") key (next to the RETURN key) and you'll get rid of the menubar. I also disabled the top assistant and bottom control panel. Just for grins.This gives you the maximum in workspace (pixel realetsate), nothing is wasted to menus, toolbars,...).

Ok ok, so I did that only to talk about this feature. It's handy though, especially if you travel with an old laptop with 640x480 pixel resolution and a 486 driving it. (yes, I've heard of someone using Amapi 3D on a good ol' 486er! with Windows 95).


2. Top View

Select the top view and line the orientation up against the main screen axes:
 

You now are looking down at the workbench:


3. Draw a Box

Swipe the cursor to the right edge and back in to switch to the right toolkit. You should see the Construction toolkit, which contains the DRAW tool: 
Click the draw tool:

Select the Rectangle tool (second from the left). You can now draw a rectangular shape, either by click/drag/releasing, or click/move/clicking again.

If you want precise dimensions, click the first point (e.g. upper-left corner of the workbench), then hit the TAB key to enter the numeric values (in lower left of screen) for the width and height.

Here's the result:

Use the ARROW keys to view the box from various angles.


 


4. Extrude the box and close (cap) it

Swipe the magic wand (cursor) to the right screen edge until to see the Construction toolkit with the Draw and Extrusion tool again. (you're probably still in this toolkit!).

Select the Extrusion tool and click the box. Notice how you can initially move the extrusion along both axes, left-right as well as up-down. We really want it just going up, so hit the SPACEBAR to toggle between axes until you have just the green (vertical) axis.

You may have the granularity too coarse and notice the size 'jumping' in large increments. Just use the +/- keys to change the granularity. Use 'plus' (+) to make it finer.

When you have the desired distance of extrusion, click the mouse, and hit RETURN. You'll see the top and bottom of the extruded surface in red, indicating it's a hole (an open surface so far) and you can click either side to close it.

Click both red ends to close the thing, it's now a volume. (you can verify that by double-clicking the box and see its properties).

You can also verify the dimensions, surface and vulome with the measurement tool in the control panel (Tools/ControlPanel/Measure from the menubar).

Once you're out of the extrusion tool and in idle mode again, hit the RETURN key to do a quick shaded rendering:


 


5. Round the corners

We should have beveled (rounded) the corners of the curve before doing the extrusion, shouldn't we? Well, here's how we apply a bevel to just a corner.
Swipe the tool away to display the modeling toolkit. Before selecting the Bevel tool, you will want to select the top and bottom point of a corner (short edge) which needs to be rounded. On Windows systems, click the right mouse button once or twice. On Mac, use the Shift-click (or was it Apple-click? I don't remember off the top of my head and don't have a Mac at home). Either way, you'll either get the bull's eye (target) cursor to select the points one by one if you click twice, or the lasso cursor

Throw the lasso over the desired points (click a shape around the desired area, you'll see a red rubberband outline appear click by click).

Hit RETURN when satisfied that the lasso contains the desired points to select (you can always add points with another lasso or bull's eye cursor later if you missed some).

The selected points are shown in red. The small white ball indicates the middle of all selected points (center of gravity if you prefer).

Switch to the Modeling toolkit with the Bevel tool

Click the Bevel tool and use the plus/minus keys to adjust the radius of the bevel,

or hit TAB to enter numeric values.

Hit Enter when done.

Repeat for other corners you want beveled: Select the corner's points, apply bevel,..

Once you've done the four corners and you're in idle mode again, hit RETURN for a quick rendering:

6. Bevel the top edges

Now we can go a little bit faster and repeat the bevel thing for the sharp edges at the top of the plate.

Use the Lasso cursor to select the points at the top. It helps to select a front view (numeric '2' key).

Apply the bevel tool to that selection, as before, and use the numeric entry mode (TAB key) to specify a small radius.

Hit ENTER when done and again to render it. Now the plate looks much better.

Notice the specular highlight now on the rounded rim?
 

7. Extract a Curve for the Pilars

One of the most powerful tools in Amapi 3D is the ability to create a curve from existing points of other curves, surfaces and columes, even from center of gravity points (that little white ball on the current object) and on mid-points of line segments!)

Zoom in on a rounded corner (using the numeric '1' key to show a zoom box you can size and position on the desired area).

You might be tempted to use the DRAW tool again and explicitly draw a curve (polyline) that lies on the existing points at the bottom of the rounded corner. We'd have to hold the SHIFT key down as we click the various points to make sure the new curve snaps to points on the existing cornerline.

But why bother? The points are already there, let's use the Extract Curve tool, click the right mouse button to select the target (bull's eye) cursor, and click the points directly (no need to SHIFT).

Here's one way to get this done: Select the lasso cursor, through it over the desired points:

You will have select a subset of the points (it's not a curve quite yet, just a selection of points).

Then select the CURVE EXTRACT tool   and throw its lasso over the selected points. You automatically get a curve going through these points.

Another method (mode meticulous and visually appealing?)is  to go straight to the CURVE EXTRACT tool and not stay with the lasso cursor but click the right mouse button again to switch to the bull's eye and select the points one by one to draw a curve through them:


 

Once you have selected the points, hit RETURN to complete the tool. The block  is no longer the current object. You see the white ball at the center of gravity of the new curve.

8. Offset the curve

We now need to have another curve that goes along this one, but is 'outside' of that circular arc. We can use the Thickness tool and in particular the 'offset' mode of it:


 

Use the plus (+) key to increase the offset. Or hit TAB to enter a numeric value for it.

When you're done, hit RETURN.

You now have another set of points, which you can use for creating a closed curve going through the inner and outer profile curves. Use the EXTRACT CURVE tool again, click all points of the inner curve from left to right then all points of the outer curve from right to left, then the starting point of the first curve again to close the curve, hit Enter when done.
 


 

You now have a closed curve going through the inner and outer profile.

Use the Extrusion tool or the Sweep tool to extrude it upwards. Use the SPACEBAR to toggle into vertical-only extrusion.

When you have the desired depth of extrusion, click, and hit RETURN.

Click the top and bottom red curves to close and hit return.

The 'pilar' is now a solid. You can double-click it to see its properties.

9. Duplicate by Rotation

We now want to create 3 more of these, by duplication, simply by rotating a sample around the center of the block.

Take the top view (numeric '2' for front, then numeric '5' for top) and zoom out (numeric '.' or '0') to see it all. Select the Assembly toolkit with the ROTATE tool.

Before clicking the rotate tool, make sure the pilar is the currently selected object.

Now we don't want to just rotate the part, we want to create a duplicate by rotation, and leave the original where it is.

Hold the CONTROL key down, click the Rotate tool. Release the CONTROL key.

We need to set the center of rotation (reference point marked by an 'X") at the center of the block. Click the right button (or select the 'X' from the assistant palette). You're now supposed to select a point to place that reference point. However there's no point visible in the middle. How do we select a geometric point (like mid point of a line) if there's nothing there? Simply hold the SHIFT key and move the cursor to the proximity of the desired point. Amapi will place a small '+' mark at the snapped location. Click the mouse to place the reference point there.

Now, click the mouse somewhere between the reference point and the pilar in the lower right (the one we're about to rotate).

A graduated scale with coarse increments (22.5 degrees) appears:

move the cursor to the next corner's side indicating the angle where you want it rotate to. You can also enter the angle (90) in numeric mode by hitting the TAB key.

Observe how the green line from the center of rotation follows your mouse motion and easily lets you snap to the right position in the upper-right.
Click the mouse again. A duplicate appears. Use the ARROW keys to view the new scene. (the original may initiall have appeared to be gone because of the rubberband XOR cursor undraw/redraw that happens in this operation). If you did have the CONTROL key down before clicking the ROTATE tool you properly have initiated and now completed a Duplication by Rotation.

Repeat this for the other two corners. In fact you can do the other two in a single operation, if you first group the two pilars into one. Use the group tool from the Control panel.

Here's a rendering of the final result:


 


10. Finish

How about the cork layer underneath (which protects the table from scratches)?
 

So, that's about all on the modeling side, now you just need a coffee table (there's one in the models collection from the CD) to put this on, and apply the right material properties. No need to worry about the cork bottom since it's not visible unless you simulate an ant's view to this thing.

11. Movies

You've seen the final renderings at the beginning. Here are a few animations (AVI movie).


199 kb AVI

898 kb AVI

If you need a free viewer I recommend Irfanview32 on Windows.
Check TUCOWS  for availability.


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